Method and device for sorting flat and indexed articles

Abstract

A method and device for sorting flat and indexed articles are disclosed, the method involving two passes. In the first pass, articles having a destination common to a very large member of articles are sorted and distributed to N/2 receptacles (10), the receptacles being fewer in number than the total number (N) of possible destinations for the articles, while the other articles are put aside in a buffer receptacle (12). In the second pass, a control circuit (7) assigns new destinations to the sorting receptacles, placing a marker (16) after each pack of articles contained in the receptacles, and the articles initially set aside (21) are resorted to the new destinations. The invention is particularly applicable to mail sorting.

I claim: 
     
       1. Method for sorting flat, indexed articles, where said articles are stored in a magazine, extracted or unpiled therefrom one by one, each article being directed past a read head recognizing its indexing, sort commands are sent to a sorting device to receive and distribute each article to a sorting receptacle corresponding to its destination according to recognized destination indexes, whereby, the number of sorting receptacles being less than the total number of possible destinations, the following steps are cyclically performed: articles having a destination for which no sorting receptacle is provided are put aside or bypassed to a buffer receptacle, while the remaining articles are sent to their respective sorting receptacles;   a marker is placed at the top of each pile of articles in the assigned sorting receptacles;   new destinations are then assigned to all the existing sorting receptacles;   and all the buffered articles are then redirected past the read head and sent to the sorting receptacles having the new destinations.   
     
     
       2. Method as in claim 1, whereby sorting is carried out in two passes, the number (N/2) of sorting receptacles being greater than or equal to half of the number (N) of possible destinations. 
     
     
       3. Method as in claim 2, whereby the second pass is carried out when the buffer receptacle has been filled up, temporarily interrupting the unpiling of articles from said magazine. 
     
     
       4. Method as in claim 2, whereby said new destinations are correlated with the first destination assignments of said sorting receptacles. 
     
     
       5. Device for sorting flat, indexed articles, consisting of a magazine containing the flat articles to be sorted, an unpiler or extractor to extract the articles therefrom one by one and direct them past a read head which recognizes the indexes, and a control circuit to receive from the read head the index information and generate sort instructions to be carried out by a sorter, wherein said sorter has a number of sorting receptacles which is less than the total amount of possible article destinations, to receive that part of the articles having destinations matching said receptacles, and a buffer receptacle to hold the articles having no matching receptacle for their destination indexes, and wherein the sorting device comprises means to interrupt said sorter, means to place a marker at the top of the pile of articles in existing-destination sorting receptacles, means to assign a new destination to each sorting receptacle and means to restart said sorter to execute the resorting of the articles initially routed to the buffer receptacle. 
     
     
       6. Device as in claim 5, wherein said marker placing means include an unpiler from a marker magazine, connected in parallel with said article magazine unpiler. 
     
     
       7. Device as in claim 5 or 6 wherein said means to execute the resorting of the articles initially routed to the buffer receptacle includes a buffer receptacle unpiler operable to seize the articles contained in said buffer receptacle and is connected to said sorter in parallel with said article magazine unpiler. 
     
     
       8. Device as in claim 5, wherein said buffer receptacle is a flow storage device for flat articles. 
     
     
       9. Device as in claim 5, wherein said buffer receptacle comprises means for detecting when it is full. 
     
     
       10. Device as in claim 5, wherein said markers feature suitable physical, magnetic, color or other coding means to make their presence obvious in a pile of articles stacked in a sorting receptacle.